Antireflection coatings, optical filters, optical lenses, spectacle lenses, beam splitters, prisms, mirrors and other optical elements and sanitary wares are liable to be stained with fingerprints, skin oil, sweat, cosmetics, etc., when used. Once adhering, such stains are not easily removed, and in particular, stains adhering to optical members with antireflection coatings are easily noticeable and pose problems.
To solve such problems relating to antifouling, techniques using various surface treatment compositions have hitherto been proposed.
For example, Japanese Examined Patent Publication No. 1994-29332 has proposed an antifouling, low-reflection plastic that has, on its surface, an antireflection coating comprising polyfluoroalkyl group-containing, mono- and disilane compounds and halogen-, alkyl- or alkoxysilane compound.
Recently, WO2006/107083 has proposed a surface treatment composition comprising organosilicon compounds bearing an alkoxysilyl functional group at the end of a fluoropolymer chain. This surface treatment composition provides a low-surface-energy layer that prevents moisture or dirt from adhering to the surface of various materials, especially antireflective films and like optical members and glasses.
However, the antifouling coatings formed by the hitherto known processes are not necessarily sufficient in anti-fouling properties, and in particular, their stain resistance fairly reduces as they are used for a longer period. Therefore, development of an antifouling coating with excellent antifouling properties and excellent durability is desired.